Earth shows a continuous increase in warming
A May 18 letter writer states that “global temperatures have not increased in the last 16 years.” If by global he means the average land surface and atmospheric temperatures, it’s a fairly accurate statement. But if global means the entire Earth, there has been no stop in warming since 1998.
His claim of no Earth warming relies on people’s confusion about the difference between weather, which fluctuates all the time, and climate, which speaks to long-term trends. In fact, the oceans, as witnessed by surface and at-depth temperatures, have continued to warm at a rate which, when averaged with the land temperatures, shows a continuous increase in the Earth’s warmth.
The leveling off of the average air temperatures since 1997-98, which the writer is citing, is the result of data cherry-picking. In those years there was a big El Nino event, which resulted in a lot of heat coming out of the ocean. Since then, there have been no large El Ninos, and several La Nina events. So, comparing post-1998 temperatures with those of the El Nino years shows an apparent lack of heating. In fact, the heat has been going back into the oceans. The next large El Nino event will probably pour that heat back into the atmosphere, restoring the average warming trend that has been seen since the turn of the 20th century.